One of the most widely used fibers for industrial garments is cotton because of its availability, cost, comfort, and the well-developed methods for spinning, weaving, and knitting, and fabricating garments from it. However, because of the abusive working or recreational conditions that such garments may be subjected to, it has been found advantageous to blend the cotton fibers with other materials, such as thermoplastic fibers (such as nylon or polyester) or thermoset fibers (such as aramid fibers). One method for treating fabrics from such blended fibers to give them flame retardant characteristics is to treat the fabrics with an aqueous solution of an organo phosphorous compound such as tetrakis (hydroxyorgano) phosphonium compound especially with a tetrakis (hydroxymethyl) phosphonium which will be hereinafter called “THP”. The use of such treatment compounds is summarized in Technical Bulletin TRI 4002 from Cotton Incorporated of Cary, N.C., Copyright 2003 entitled: Fabric Flame Retardant Treatment “Precondensate”/NH3Process. Among the many other examples in the prior art are U.S. Pat. No. 4,909,805 to Geoffrey W. Smith, U.S. Pat. No. 4,900,613 to James R. Green, and U.S. Pat. No. 5,468,545 to George R. Fleming, et al.
The process for using THP in an aqueous solution to treat fabrics of cotton blends to impart flame retardant characteristics as described in the above-mentioned Smith and Fleming patents begins when the fabric to be treated is dipped into a bath containing THP in a specified concentration and pulled therethrough.
Other methods to hold and convey fabrics in order to apply a variety of treatments include dyeing a fabric on a frame as shown in U.S. Pat. No. 4,717,391 by spraying the dye onto the fabric and coating as shown in U.S. Pat. No. 4,062,989 to Delmar D. Long, where fabric is held by a pin tenter frame to receive a coating layer and in U.S. Pat. No. 3,637,409 to Ludwig Hartman, where a non-woven fabric is coated and is impregnated with a flame retardant after being first stretched longitudinally followed by re-wetting and stretching transversely. In addition, in U.S. Pat. No. 4,051,699 to John Carpenter, a process is described where fabric is held on a pin drive to maintain tension while liquid ammonia is applied to the fabric. Accordingly, it is one object of the present invention to provide a novel method of treating a woven or knitted fabric with a flame retardant while being conveyed.
In US Patent Publication 2005/0272838 A1 to Charles Yang, et al. the treatment of cotton and/or cotton blends containing Nomex®, Kevlar®, nylon, and polyester fiber in a flame retardant material is described. The treatment employs a melamine-formaldehyde resin. Accordingly, it is another object of the invention to provide a woven or knitted fabric of novel cotton/thermoplastic/thermoset fiber blends which are treated by a unique method of applying flame retardant.
Another hazard encountered with apparel fabrics, particularly in cool, dry environments, is electrostatic discharge or “sparking.” Also, many other environments can cause a buildup of electrostatic charge because of the proximity to high voltage lines or equipment. The inadvertent discharge or spark from a charged garment while the wearer is near a volatile substance can result in serious fire or explosion. In U.S. Pat. No. 4,557,968 to Thornton et al., issued Dec. 10, 1985, a directional electrostatic discharging fabric is described that employs carbon and polyester fibers with the purpose of conducting away any charge before it can build up. Accordingly, it is another object of the present invention to provide a garment that reduces the hazards of electrostatic buildup and discharge.
The foregoing and other objects are accomplished by the invention described below.